CONCRETE OUSTED

Wanganui Chronicle, Volume LXXXIII, Issue 19918, 13 August 1927, Page 6

CONCRETE OUSTED

SHELL ROCK PREVAILS EXPERIMENTS IN MOLE COJ STRUCTIOjff Details of t'he sample concrete blocks for mole construction, which are being manufactured at the Castlecliff Wharf by Mr J. R-amsay, late engineer to the Gonville Town Board were placed before tho Wanganui Harbour Board last evening, and an interesting discussion on the relative costs and values of concrete blocks and shell rock ensued. The chairman (Mr A. G- Bigneß) did not think that Mr Ramsay had. shown the Board, anything that it did not already know, and in any case the statement that the blocks could be made at 16s 6d and 17s 6d a ton was only an estimate. The Board had enough shell rock exposed at the quarries to last another two monthand shell rock, which had been proved for the last 45 years was eminently suited for the Board’s work. The shell rock cost the Board Ils a ton and practically the whole expense went in wages. With concrete blocks half the cost would go in buying cement. The Board was paying Mr Ramsay’s expenses. The chairman said that when a new supply of material was wanted for building moles, the Board would investigate every source of supply. He believed he could go io a rock deposit that would mean a far less cost to the Board than concrete. Mr W. Bruce asked if it were not a fact that concrete blocks would mean that less material would be required to make a mole than would be the case where shell rock was used. The chairman said that experienc? at other ports in New Zealand had shown that a solid concrete wall would not withstand heavy seas and loose rock had to be dumped for protection. Mr J. Patterson stressed the necessity for keying the concrete blocks so that a solid wall was the result, but the Board’s engineer (Mr H. V. M. Haszard) remarked that it was all very well to key concrete blocks but they must first be keyed to New Zealand. Where they ‘had no solid founda tion the only thing to do was t< tumble the blocks in pell-mell. At th< entrance to the Wanganui port thej had only a foundation of sand.